2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * All elements have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * An existing pad of an element can be retrieved by name with
45 * gst_element_get_static_pad(). A new dynamic pad can be created using
46 * gst_element_request_pad() with a #GstPadTemplate or
47 * gst_element_get_request_pad() with the template name such as "src_\%d".
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * gst_element_provides_clock() returns %TRUE. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If
72 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock slection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
79 * Last reviewed on 2009-05-29 (0.10.24)
82 #include "gst_private.h"
85 #include <gobject/gvaluecollector.h>
87 #include "gstelement.h"
88 #include "gstelementmetadata.h"
89 #include "gstenumtypes.h"
91 #include "gstmarshal.h"
97 #include "gst-i18n-lib.h"
99 /* Element signals and args */
115 static void gst_element_class_init (GstElementClass * klass);
116 static void gst_element_init (GstElement * element);
117 static void gst_element_base_class_init (gpointer g_class);
118 static void gst_element_base_class_finalize (gpointer g_class);
120 static void gst_element_dispose (GObject * object);
121 static void gst_element_finalize (GObject * object);
123 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
124 GstStateChange transition);
125 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
126 GstState * state, GstState * pending, GstClockTime timeout);
127 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
129 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
131 static gboolean gst_element_default_send_event (GstElement * element,
133 static gboolean gst_element_default_query (GstElement * element,
136 static GstPadTemplate
137 * gst_element_class_get_request_pad_template (GstElementClass *
138 element_class, const gchar * name);
140 static GstObjectClass *parent_class = NULL;
141 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
143 /* this is used in gstelementfactory.c:gst_element_register() */
144 GQuark __gst_elementclass_factory = 0;
147 gst_element_get_type (void)
149 static volatile gsize gst_element_type = 0;
151 if (g_once_init_enter (&gst_element_type)) {
153 static const GTypeInfo element_info = {
154 sizeof (GstElementClass),
155 gst_element_base_class_init,
156 gst_element_base_class_finalize,
157 (GClassInitFunc) gst_element_class_init,
162 (GInstanceInitFunc) gst_element_init,
166 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
167 &element_info, G_TYPE_FLAG_ABSTRACT);
169 __gst_elementclass_factory =
170 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
171 g_once_init_leave (&gst_element_type, _type);
173 return gst_element_type;
177 gst_element_class_init (GstElementClass * klass)
179 GObjectClass *gobject_class;
181 gobject_class = (GObjectClass *) klass;
183 parent_class = g_type_class_peek_parent (klass);
186 * GstElement::pad-added:
187 * @gstelement: the object which received the signal
188 * @new_pad: the pad that has been added
190 * a new #GstPad has been added to the element. Note that this signal will
191 * usually be emitted from the context of the streaming thread. Also keep in
192 * mind that if you add new elements to the pipeline in the signal handler
193 * you will need to set them to the desired target state with
194 * gst_element_set_state() or gst_element_sync_state_with_parent().
196 gst_element_signals[PAD_ADDED] =
197 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
198 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
199 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
201 * GstElement::pad-removed:
202 * @gstelement: the object which received the signal
203 * @old_pad: the pad that has been removed
205 * a #GstPad has been removed from the element
207 gst_element_signals[PAD_REMOVED] =
208 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
209 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
210 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
212 * GstElement::no-more-pads:
213 * @gstelement: the object which received the signal
215 * This signals that the element will not generate more dynamic pads.
216 * Note that this signal will usually be emitted from the context of
217 * the streaming thread.
219 gst_element_signals[NO_MORE_PADS] =
220 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
221 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
222 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
224 gobject_class->dispose = gst_element_dispose;
225 gobject_class->finalize = gst_element_finalize;
227 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
228 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
229 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
230 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
231 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
232 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
233 klass->numpadtemplates = 0;
235 klass->elementfactory = NULL;
239 gst_element_base_class_init (gpointer g_class)
241 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
242 GList *node, *padtemplates;
244 /* Copy the element details here so elements can inherit the
245 * details from their base class and classes only need to set
246 * the details in class_init instead of base_init */
247 element_class->metadata =
248 element_class->metadata ? gst_structure_copy (element_class->metadata) :
249 gst_structure_new_empty ("metadata");
251 /* Copy the pad templates so elements inherit them
252 * from their base class but elements can add pad templates in class_init
253 * instead of base_init.
255 padtemplates = g_list_copy (element_class->padtemplates);
256 for (node = padtemplates; node != NULL; node = node->next) {
257 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
258 gst_object_ref (tmpl);
260 element_class->padtemplates = padtemplates;
262 /* set the factory, see gst_element_register() */
263 element_class->elementfactory =
264 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
265 __gst_elementclass_factory);
266 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
267 element_class->elementfactory);
271 gst_element_base_class_finalize (gpointer g_class)
273 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
275 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
276 g_list_free (klass->padtemplates);
278 gst_structure_free (klass->metadata);
282 gst_element_init (GstElement * element)
284 GST_STATE (element) = GST_STATE_NULL;
285 GST_STATE_TARGET (element) = GST_STATE_NULL;
286 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
287 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
288 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
290 g_static_rec_mutex_init (&element->state_lock);
291 element->state_cond = g_cond_new ();
295 * gst_element_release_request_pad:
296 * @element: a #GstElement to release the request pad of.
297 * @pad: the #GstPad to release.
299 * Makes the element free the previously requested pad as obtained
300 * with gst_element_get_request_pad().
302 * This does not unref the pad. If the pad was created by using
303 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
304 * followed by gst_object_unref() to free the @pad.
309 gst_element_release_request_pad (GstElement * element, GstPad * pad)
311 GstElementClass *oclass;
313 g_return_if_fail (GST_IS_ELEMENT (element));
314 g_return_if_fail (GST_IS_PAD (pad));
316 oclass = GST_ELEMENT_GET_CLASS (element);
318 /* if the element implements a custom release function we call that, else we
319 * simply remove the pad from the element */
320 if (oclass->release_pad)
321 (oclass->release_pad) (element, pad);
323 gst_element_remove_pad (element, pad);
327 * gst_element_requires_clock:
328 * @element: a #GstElement to query
330 * Query if the element requires a clock.
332 * Returns: %TRUE if the element requires a clock
337 gst_element_requires_clock (GstElement * element)
341 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
343 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
349 * gst_element_provides_clock:
350 * @element: a #GstElement to query
352 * Query if the element provides a clock. A #GstClock provided by an
353 * element can be used as the global #GstClock for the pipeline.
354 * An element that can provide a clock is only required to do so in the PAUSED
355 * state, this means when it is fully negotiated and has allocated the resources
356 * to operate the clock.
358 * Returns: %TRUE if the element provides a clock
363 gst_element_provides_clock (GstElement * element)
367 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
369 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
375 * gst_element_provide_clock:
376 * @element: a #GstElement to query
378 * Get the clock provided by the given element.
379 * <note>An element is only required to provide a clock in the PAUSED
380 * state. Some elements can provide a clock in other states.</note>
382 * Returns: (transfer full): the GstClock provided by the element or %NULL
383 * if no clock could be provided. Unref after usage.
388 gst_element_provide_clock (GstElement * element)
390 GstClock *result = NULL;
391 GstElementClass *oclass;
393 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
395 oclass = GST_ELEMENT_GET_CLASS (element);
397 if (oclass->provide_clock)
398 result = oclass->provide_clock (element);
404 * gst_element_set_clock:
405 * @element: a #GstElement to set the clock for.
406 * @clock: the #GstClock to set for the element.
408 * Sets the clock for the element. This function increases the
409 * refcount on the clock. Any previously set clock on the object
412 * Returns: %TRUE if the element accepted the clock. An element can refuse a
413 * clock when it, for example, is not able to slave its internal clock to the
414 * @clock or when it requires a specific clock to operate.
419 gst_element_set_clock (GstElement * element, GstClock * clock)
421 GstElementClass *oclass;
425 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
426 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
428 oclass = GST_ELEMENT_GET_CLASS (element);
430 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
432 if (oclass->set_clock)
433 res = oclass->set_clock (element, clock);
436 /* only update the clock pointer if the element accepted the clock */
437 GST_OBJECT_LOCK (element);
438 clock_p = &element->clock;
439 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
440 GST_OBJECT_UNLOCK (element);
446 * gst_element_get_clock:
447 * @element: a #GstElement to get the clock of.
449 * Gets the currently configured clock of the element. This is the clock as was
450 * last set with gst_element_set_clock().
452 * Returns: (transfer full): the #GstClock of the element. unref after usage.
457 gst_element_get_clock (GstElement * element)
461 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
463 GST_OBJECT_LOCK (element);
464 if ((result = element->clock))
465 gst_object_ref (result);
466 GST_OBJECT_UNLOCK (element);
472 * gst_element_set_base_time:
473 * @element: a #GstElement.
474 * @time: the base time to set.
476 * Set the base time of an element. See gst_element_get_base_time().
481 gst_element_set_base_time (GstElement * element, GstClockTime time)
485 g_return_if_fail (GST_IS_ELEMENT (element));
487 GST_OBJECT_LOCK (element);
488 old = element->base_time;
489 element->base_time = time;
490 GST_OBJECT_UNLOCK (element);
492 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
493 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
494 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
498 * gst_element_get_base_time:
499 * @element: a #GstElement.
501 * Returns the base time of the element. The base time is the
502 * absolute time of the clock when this element was last put to
503 * PLAYING. Subtracting the base time from the clock time gives
504 * the running time of the element.
506 * Returns: the base time of the element.
511 gst_element_get_base_time (GstElement * element)
515 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
517 GST_OBJECT_LOCK (element);
518 result = element->base_time;
519 GST_OBJECT_UNLOCK (element);
525 * gst_element_set_start_time:
526 * @element: a #GstElement.
527 * @time: the base time to set.
529 * Set the start time of an element. The start time of the element is the
530 * running time of the element when it last went to the PAUSED state. In READY
531 * or after a flushing seek, it is set to 0.
533 * Toplevel elements like #GstPipeline will manage the start_time and
534 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
535 * on such a toplevel element will disable the distribution of the base_time to
536 * the children and can be useful if the application manages the base_time
537 * itself, for example if you want to synchronize capture from multiple
538 * pipelines, and you can also ensure that the pipelines have the same clock.
545 gst_element_set_start_time (GstElement * element, GstClockTime time)
549 g_return_if_fail (GST_IS_ELEMENT (element));
551 GST_OBJECT_LOCK (element);
552 old = GST_ELEMENT_START_TIME (element);
553 GST_ELEMENT_START_TIME (element) = time;
554 GST_OBJECT_UNLOCK (element);
556 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
557 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
558 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
562 * gst_element_get_start_time:
563 * @element: a #GstElement.
565 * Returns the start time of the element. The start time is the
566 * running time of the clock when this element was last put to PAUSED.
568 * Usually the start_time is managed by a toplevel element such as
573 * Returns: the start time of the element.
578 gst_element_get_start_time (GstElement * element)
582 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
584 GST_OBJECT_LOCK (element);
585 result = GST_ELEMENT_START_TIME (element);
586 GST_OBJECT_UNLOCK (element);
592 * gst_element_is_indexable:
593 * @element: a #GstElement.
595 * Queries if the element can be indexed.
597 * Returns: TRUE if the element can be indexed.
602 gst_element_is_indexable (GstElement * element)
606 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
608 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
614 * gst_element_set_index:
615 * @element: a #GstElement.
616 * @index: (transfer none): a #GstIndex.
618 * Set @index on the element. The refcount of the index
619 * will be increased, any previously set index is unreffed.
624 gst_element_set_index (GstElement * element, GstIndex * index)
626 GstElementClass *oclass;
628 g_return_if_fail (GST_IS_ELEMENT (element));
629 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
631 oclass = GST_ELEMENT_GET_CLASS (element);
633 if (oclass->set_index)
634 oclass->set_index (element, index);
638 * gst_element_get_index:
639 * @element: a #GstElement.
641 * Gets the index from the element.
643 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
644 * element. unref after usage.
649 gst_element_get_index (GstElement * element)
651 GstElementClass *oclass;
652 GstIndex *result = NULL;
654 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
656 oclass = GST_ELEMENT_GET_CLASS (element);
658 if (oclass->get_index)
659 result = oclass->get_index (element);
665 * gst_element_add_pad:
666 * @element: a #GstElement to add the pad to.
667 * @pad: (transfer full): the #GstPad to add to the element.
669 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
670 * see gst_object_set_parent() for refcounting information.
672 * Pads are not automatically activated so elements should perform the needed
673 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
674 * state. See gst_pad_set_active() for more information about activating pads.
676 * The pad and the element should be unlocked when calling this function.
678 * This function will emit the #GstElement::pad-added signal on the element.
680 * Returns: %TRUE if the pad could be added. This function can fail when
681 * a pad with the same name already existed or the pad already had another
687 gst_element_add_pad (GstElement * element, GstPad * pad)
692 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
693 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
695 /* locking pad to look at the name */
696 GST_OBJECT_LOCK (pad);
697 pad_name = g_strdup (GST_PAD_NAME (pad));
698 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
699 GST_STR_NULL (pad_name));
700 flushing = GST_PAD_IS_FLUSHING (pad);
701 GST_OBJECT_UNLOCK (pad);
703 /* then check to see if there's already a pad by that name here */
704 GST_OBJECT_LOCK (element);
705 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
708 /* try to set the pad's parent */
709 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
710 GST_OBJECT_CAST (element))))
713 /* check for flushing pads */
714 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
715 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
716 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
717 "use gst_pad_set_active(pad,TRUE) before adding it.",
718 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
720 GST_OBJECT_LOCK (pad);
721 GST_PAD_UNSET_FLUSHING (pad);
722 GST_OBJECT_UNLOCK (pad);
727 /* add it to the list */
728 switch (gst_pad_get_direction (pad)) {
730 element->srcpads = g_list_prepend (element->srcpads, pad);
731 element->numsrcpads++;
734 element->sinkpads = g_list_prepend (element->sinkpads, pad);
735 element->numsinkpads++;
740 element->pads = g_list_prepend (element->pads, pad);
742 element->pads_cookie++;
743 GST_OBJECT_UNLOCK (element);
745 /* emit the PAD_ADDED signal */
746 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
753 g_critical ("Padname %s is not unique in element %s, not adding",
754 pad_name, GST_ELEMENT_NAME (element));
755 GST_OBJECT_UNLOCK (element);
762 ("Pad %s already has parent when trying to add to element %s",
763 pad_name, GST_ELEMENT_NAME (element));
764 GST_OBJECT_UNLOCK (element);
770 GST_OBJECT_LOCK (pad);
772 ("Trying to add pad %s to element %s, but it has no direction",
773 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
774 GST_OBJECT_UNLOCK (pad);
775 GST_OBJECT_UNLOCK (element);
781 * gst_element_remove_pad:
782 * @element: a #GstElement to remove pad from.
783 * @pad: (transfer none): the #GstPad to remove from the element.
785 * Removes @pad from @element. @pad will be destroyed if it has not been
786 * referenced elsewhere using gst_object_unparent().
788 * This function is used by plugin developers and should not be used
789 * by applications. Pads that were dynamically requested from elements
790 * with gst_element_get_request_pad() should be released with the
791 * gst_element_release_request_pad() function instead.
793 * Pads are not automatically deactivated so elements should perform the needed
794 * steps to deactivate the pad in case this pad is removed in the PAUSED or
795 * PLAYING state. See gst_pad_set_active() for more information about
798 * The pad and the element should be unlocked when calling this function.
800 * This function will emit the #GstElement::pad-removed signal on the element.
802 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
803 * pad does not belong to the provided element.
808 gst_element_remove_pad (GstElement * element, GstPad * pad)
812 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
813 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
815 /* locking pad to look at the name and parent */
816 GST_OBJECT_LOCK (pad);
817 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
818 GST_STR_NULL (GST_PAD_NAME (pad)));
820 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
822 GST_OBJECT_UNLOCK (pad);
825 if ((peer = gst_pad_get_peer (pad))) {
826 /* window for MT unsafeness, someone else could unlink here
827 * and then we call unlink with wrong pads. The unlink
828 * function would catch this and safely return failed. */
829 if (GST_PAD_IS_SRC (pad))
830 gst_pad_unlink (pad, peer);
832 gst_pad_unlink (peer, pad);
834 gst_object_unref (peer);
837 GST_OBJECT_LOCK (element);
838 /* remove it from the list */
839 switch (gst_pad_get_direction (pad)) {
841 element->srcpads = g_list_remove (element->srcpads, pad);
842 element->numsrcpads--;
845 element->sinkpads = g_list_remove (element->sinkpads, pad);
846 element->numsinkpads--;
849 g_critical ("Removing pad without direction???");
852 element->pads = g_list_remove (element->pads, pad);
854 element->pads_cookie++;
855 GST_OBJECT_UNLOCK (element);
857 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
858 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
860 gst_object_unparent (GST_OBJECT_CAST (pad));
867 /* locking order is element > pad */
868 GST_OBJECT_UNLOCK (pad);
870 GST_OBJECT_LOCK (element);
871 GST_OBJECT_LOCK (pad);
872 g_critical ("Padname %s:%s does not belong to element %s when removing",
873 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
874 GST_OBJECT_UNLOCK (pad);
875 GST_OBJECT_UNLOCK (element);
881 * gst_element_no_more_pads:
882 * @element: a #GstElement
884 * Use this function to signal that the element does not expect any more pads
885 * to show up in the current pipeline. This function should be called whenever
886 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
887 * pad templates use this in combination with autopluggers to figure out that
888 * the element is done initializing its pads.
890 * This function emits the #GstElement::no-more-pads signal.
895 gst_element_no_more_pads (GstElement * element)
897 g_return_if_fail (GST_IS_ELEMENT (element));
899 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
903 pad_compare_name (GstPad * pad1, const gchar * name)
907 GST_OBJECT_LOCK (pad1);
908 result = strcmp (GST_PAD_NAME (pad1), name);
909 GST_OBJECT_UNLOCK (pad1);
915 * gst_element_get_static_pad:
916 * @element: a #GstElement to find a static pad of.
917 * @name: the name of the static #GstPad to retrieve.
919 * Retrieves a pad from @element by name. This version only retrieves
920 * already-existing (i.e. 'static') pads.
922 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
928 gst_element_get_static_pad (GstElement * element, const gchar * name)
931 GstPad *result = NULL;
933 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
934 g_return_val_if_fail (name != NULL, NULL);
936 GST_OBJECT_LOCK (element);
938 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
940 result = GST_PAD_CAST (find->data);
941 gst_object_ref (result);
944 if (result == NULL) {
945 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
946 name, GST_ELEMENT_NAME (element));
948 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
949 GST_ELEMENT_NAME (element), name);
951 GST_OBJECT_UNLOCK (element);
957 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
958 const gchar * name, const GstCaps * caps)
960 GstPad *newpad = NULL;
961 GstElementClass *oclass;
963 oclass = GST_ELEMENT_GET_CLASS (element);
965 #ifndef G_DISABLE_CHECKS
966 /* Some sanity checking here */
970 /* Is this the template name? */
971 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
972 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
974 const gchar *str, *data;
977 /* Otherwise check if it's a valid name for the name template */
978 str = strchr (templ->name_template, '%');
979 g_return_val_if_fail (str != NULL, NULL);
980 g_return_val_if_fail (strncmp (templ->name_template, name,
981 str - templ->name_template) == 0, NULL);
982 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
984 data = name + (str - templ->name_template);
986 /* Can either be %s or %d or %u, do sanity checking for %d */
987 if (*(str + 1) == 'd') {
991 tmp = g_ascii_strtoll (data, &endptr, 10);
992 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
993 && *endptr == '\0', NULL);
994 } else if (*(str + 1) == 'u') {
998 tmp = g_ascii_strtoull (data, &endptr, 10);
999 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
1003 pad = gst_element_get_static_pad (element, name);
1005 gst_object_unref (pad);
1006 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1007 g_critical ("Element %s already has a pad named %s, the behaviour of "
1008 " gst_element_get_request_pad() for existing pads is undefined!",
1009 GST_ELEMENT_NAME (element), name);
1014 if (oclass->request_new_pad)
1015 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1018 gst_object_ref (newpad);
1024 * gst_element_get_request_pad:
1025 * @element: a #GstElement to find a request pad of.
1026 * @name: the name of the request #GstPad to retrieve.
1028 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1029 * retrieves request pads. The pad should be released with
1030 * gst_element_release_request_pad().
1032 * This method is slow and will be deprecated in the future. New code should
1033 * use gst_element_request_pad() with the requested template.
1035 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1036 * Release after usage.
1039 gst_element_get_request_pad (GstElement * element, const gchar * name)
1041 GstPadTemplate *templ = NULL;
1043 const gchar *req_name = NULL;
1044 gboolean templ_found = FALSE;
1047 gchar *str, *endptr = NULL;
1048 GstElementClass *class;
1050 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1051 g_return_val_if_fail (name != NULL, NULL);
1053 class = GST_ELEMENT_GET_CLASS (element);
1055 /* if the name contains a %, we assume it's the complete template name. Get
1056 * the template and try to get a pad */
1057 if (strstr (name, "%")) {
1058 templ = gst_element_class_get_request_pad_template (class, name);
1063 /* there is no % in the name, try to find a matching template */
1064 list = class->padtemplates;
1065 while (!templ_found && list) {
1066 templ = (GstPadTemplate *) list->data;
1067 if (templ->presence == GST_PAD_REQUEST) {
1068 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1069 templ->name_template);
1070 /* see if we find an exact match */
1071 if (strcmp (name, templ->name_template) == 0) {
1076 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1077 and %d and %u, occurring at the end of the name_template, are the only
1079 else if ((str = strchr (templ->name_template, '%'))
1080 && strncmp (templ->name_template, name,
1081 str - templ->name_template) == 0
1082 && strlen (name) > str - templ->name_template) {
1083 data = name + (str - templ->name_template);
1084 if (*(str + 1) == 'd') {
1088 tmp = strtol (data, &endptr, 10);
1089 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1095 } else if (*(str + 1) == 'u') {
1099 tmp = strtoul (data, &endptr, 10);
1100 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1120 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1126 * gst_element_request_pad:
1127 * @element: a #GstElement to find a request pad of.
1128 * @templ: a #GstPadTemplate of which we want a pad of.
1129 * @name: (transfer none) (allow-none): the name of the request #GstPad
1130 * to retrieve. Can be %NULL.
1131 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1132 * request. Can be %NULL.
1134 * Retrieves a request pad from the element according to the provided template.
1135 * Pad templates can be looked up using
1136 * gst_element_factory_get_static_pad_templates().
1138 * If the @caps are specified and the element implements thew new
1139 * request_new_pad_full virtual method, the element will use them to select
1140 * which pad to create.
1142 * The pad should be released with gst_element_release_request_pad().
1144 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1145 * Release after usage.
1150 gst_element_request_pad (GstElement * element,
1151 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1153 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1154 g_return_val_if_fail (templ != NULL, NULL);
1156 return _gst_element_request_pad (element, templ, name, caps);
1159 static GstIterator *
1160 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1162 GstIterator *result;
1164 GST_OBJECT_LOCK (element);
1165 result = gst_iterator_new_list (GST_TYPE_PAD,
1166 GST_OBJECT_GET_LOCK (element),
1167 &element->pads_cookie, padlist, (GObject *) element, NULL);
1168 GST_OBJECT_UNLOCK (element);
1174 * gst_element_iterate_pads:
1175 * @element: a #GstElement to iterate pads of.
1177 * Retrieves an iterator of @element's pads. The iterator should
1178 * be freed after usage. Also more specialized iterators exists such as
1179 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1181 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1187 gst_element_iterate_pads (GstElement * element)
1189 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1191 return gst_element_iterate_pad_list (element, &element->pads);
1195 * gst_element_iterate_src_pads:
1196 * @element: a #GstElement.
1198 * Retrieves an iterator of @element's source pads.
1200 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1206 gst_element_iterate_src_pads (GstElement * element)
1208 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1210 return gst_element_iterate_pad_list (element, &element->srcpads);
1214 * gst_element_iterate_sink_pads:
1215 * @element: a #GstElement.
1217 * Retrieves an iterator of @element's sink pads.
1219 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1225 gst_element_iterate_sink_pads (GstElement * element)
1227 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1229 return gst_element_iterate_pad_list (element, &element->sinkpads);
1233 * gst_element_class_add_pad_template:
1234 * @klass: the #GstElementClass to add the pad template to.
1235 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1237 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1238 * functions of classes. If a pad template with the same name as an already
1239 * existing one is added the old one is replaced by the new one.
1243 gst_element_class_add_pad_template (GstElementClass * klass,
1244 GstPadTemplate * templ)
1246 GList *template_list = klass->padtemplates;
1248 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1249 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1251 /* If we already have a pad template with the same name replace the
1253 while (template_list) {
1254 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1256 /* Found pad with the same name, replace and return */
1257 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1258 gst_object_unref (padtempl);
1259 template_list->data = templ;
1262 template_list = g_list_next (template_list);
1265 /* Take ownership of the floating ref */
1266 g_object_ref_sink (templ);
1268 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1269 klass->numpadtemplates++;
1273 * gst_element_class_add_metadata:
1274 * @klass: class to set metadata for
1275 * @key: the key to set
1276 * @value: the value to set
1278 * Set @key with @value as metadata in @klass.
1281 gst_element_class_add_metadata (GstElementClass * klass,
1282 const gchar * key, const gchar * value)
1284 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1285 g_return_if_fail (key != NULL);
1286 g_return_if_fail (value != NULL);
1288 gst_structure_set ((GstStructure *) klass->metadata,
1289 key, G_TYPE_STRING, value, NULL);
1293 * gst_element_class_set_metadata:
1294 * @klass: class to set metadata for
1295 * @longname: The long English name of the element. E.g. "File Sink"
1296 * @classification: String describing the type of element, as an unordered list
1297 * separated with slashes ('/'). See draft-klass.txt of the design docs
1298 * for more details and common types. E.g: "Sink/File"
1299 * @description: Sentence describing the purpose of the element.
1300 * E.g: "Write stream to a file"
1301 * @author: Name and contact details of the author(s). Use \n to separate
1302 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1304 * Sets the detailed information for a #GstElementClass.
1305 * <note>This function is for use in _class_init functions only.</note>
1308 gst_element_class_set_metadata (GstElementClass * klass,
1309 const gchar * longname, const gchar * classification,
1310 const gchar * description, const gchar * author)
1312 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1314 gst_structure_set ((GstStructure *) klass->metadata,
1315 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1316 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1317 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1318 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1322 * gst_element_class_get_metadata:
1323 * @klass: class to get metadata for
1324 * @key: the key to get
1326 * Get metadata with @key in @klass.
1328 * Returns: the metadata for @key.
1331 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1333 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1334 g_return_val_if_fail (key != NULL, NULL);
1336 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1340 * gst_element_class_get_pad_template_list:
1341 * @element_class: a #GstElementClass to get pad templates of.
1343 * Retrieves a list of the pad templates associated with @element_class. The
1344 * list must not be modified by the calling code.
1345 * <note>If you use this function in the #GInstanceInitFunc of an object class
1346 * that has subclasses, make sure to pass the g_class parameter of the
1347 * #GInstanceInitFunc here.</note>
1349 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1353 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1355 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1357 return element_class->padtemplates;
1361 * gst_element_class_get_pad_template:
1362 * @element_class: a #GstElementClass to get the pad template of.
1363 * @name: the name of the #GstPadTemplate to get.
1365 * Retrieves a padtemplate from @element_class with the given name.
1366 * <note>If you use this function in the #GInstanceInitFunc of an object class
1367 * that has subclasses, make sure to pass the g_class parameter of the
1368 * #GInstanceInitFunc here.</note>
1370 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1371 * if none was found. No unreferencing is necessary.
1374 gst_element_class_get_pad_template (GstElementClass *
1375 element_class, const gchar * name)
1379 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1380 g_return_val_if_fail (name != NULL, NULL);
1382 padlist = element_class->padtemplates;
1385 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1387 if (strcmp (padtempl->name_template, name) == 0)
1390 padlist = g_list_next (padlist);
1396 static GstPadTemplate *
1397 gst_element_class_get_request_pad_template (GstElementClass *
1398 element_class, const gchar * name)
1400 GstPadTemplate *tmpl;
1402 tmpl = gst_element_class_get_pad_template (element_class, name);
1403 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1409 /* get a random pad on element of the given direction.
1410 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1413 gst_element_get_random_pad (GstElement * element,
1414 gboolean need_linked, GstPadDirection dir)
1416 GstPad *result = NULL;
1419 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1423 GST_OBJECT_LOCK (element);
1424 pads = element->srcpads;
1427 GST_OBJECT_LOCK (element);
1428 pads = element->sinkpads;
1431 goto wrong_direction;
1433 for (; pads; pads = g_list_next (pads)) {
1434 GstPad *pad = GST_PAD_CAST (pads->data);
1436 GST_OBJECT_LOCK (pad);
1437 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1438 GST_DEBUG_PAD_NAME (pad));
1440 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1441 /* if we require a linked pad, and it is not linked, continue the
1443 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1444 GST_DEBUG_PAD_NAME (pad));
1445 GST_OBJECT_UNLOCK (pad);
1448 /* found a pad, stop search */
1449 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1450 GST_DEBUG_PAD_NAME (pad));
1451 GST_OBJECT_UNLOCK (pad);
1457 gst_object_ref (result);
1459 GST_OBJECT_UNLOCK (element);
1463 /* ERROR handling */
1466 g_warning ("unknown pad direction %d", dir);
1472 gst_element_default_send_event (GstElement * element, GstEvent * event)
1474 gboolean result = FALSE;
1477 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1478 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1479 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1482 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1483 "pushing %s event to random %s pad %s:%s",
1484 GST_EVENT_TYPE_NAME (event),
1485 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1486 GST_DEBUG_PAD_NAME (pad));
1488 result = gst_pad_push_event (pad, event);
1489 gst_object_unref (pad);
1491 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1492 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1493 gst_event_unref (event);
1499 * gst_element_send_event:
1500 * @element: a #GstElement to send the event to.
1501 * @event: (transfer full): the #GstEvent to send to the element.
1503 * Sends an event to an element. If the element doesn't implement an
1504 * event handler, the event will be pushed on a random linked sink pad for
1505 * upstream events or a random linked source pad for downstream events.
1507 * This function takes owership of the provided event so you should
1508 * gst_event_ref() it if you want to reuse the event after this call.
1510 * Returns: %TRUE if the event was handled.
1515 gst_element_send_event (GstElement * element, GstEvent * event)
1517 GstElementClass *oclass;
1518 gboolean result = FALSE;
1520 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1521 g_return_val_if_fail (event != NULL, FALSE);
1523 oclass = GST_ELEMENT_GET_CLASS (element);
1525 GST_STATE_LOCK (element);
1526 if (oclass->send_event) {
1527 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1528 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1529 result = oclass->send_event (element, event);
1531 result = gst_element_default_send_event (element, event);
1533 GST_STATE_UNLOCK (element);
1540 * @element: a #GstElement to send the event to.
1541 * @rate: The new playback rate
1542 * @format: The format of the seek values
1543 * @flags: The optional seek flags.
1544 * @cur_type: The type and flags for the new current position
1545 * @cur: The value of the new current position
1546 * @stop_type: The type and flags for the new stop position
1547 * @stop: The value of the new stop position
1549 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1550 * the parameters. The seek event is sent to the element using
1551 * gst_element_send_event().
1553 * Returns: %TRUE if the event was handled.
1558 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1559 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1560 GstSeekType stop_type, gint64 stop)
1565 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1568 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1569 result = gst_element_send_event (element, event);
1575 gst_element_default_query (GstElement * element, GstQuery * query)
1577 gboolean result = FALSE;
1580 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1582 result = gst_pad_query (pad, query);
1584 gst_object_unref (pad);
1586 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1588 GstPad *peer = gst_pad_get_peer (pad);
1591 result = gst_pad_query (peer, query);
1593 gst_object_unref (peer);
1595 gst_object_unref (pad);
1602 * gst_element_query:
1603 * @element: a #GstElement to perform the query on.
1604 * @query: (transfer none): the #GstQuery.
1606 * Performs a query on the given element.
1608 * For elements that don't implement a query handler, this function
1609 * forwards the query to a random srcpad or to the peer of a
1610 * random linked sinkpad of this element.
1612 * Please note that some queries might need a running pipeline to work.
1614 * Returns: TRUE if the query could be performed.
1619 gst_element_query (GstElement * element, GstQuery * query)
1621 GstElementClass *oclass;
1622 gboolean result = FALSE;
1624 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1625 g_return_val_if_fail (query != NULL, FALSE);
1627 oclass = GST_ELEMENT_GET_CLASS (element);
1629 if (oclass->query) {
1630 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1631 GST_ELEMENT_NAME (element));
1632 result = oclass->query (element, query);
1634 result = gst_element_default_query (element, query);
1640 * gst_element_post_message:
1641 * @element: a #GstElement posting the message
1642 * @message: (transfer full): a #GstMessage to post
1644 * Post a message on the element's #GstBus. This function takes ownership of the
1645 * message; if you want to access the message after this call, you should add an
1646 * additional reference before calling.
1648 * Returns: %TRUE if the message was successfully posted. The function returns
1649 * %FALSE if the element did not have a bus.
1654 gst_element_post_message (GstElement * element, GstMessage * message)
1657 gboolean result = FALSE;
1659 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1660 g_return_val_if_fail (message != NULL, FALSE);
1662 GST_OBJECT_LOCK (element);
1665 if (G_UNLIKELY (bus == NULL))
1668 gst_object_ref (bus);
1669 GST_OBJECT_UNLOCK (element);
1671 /* we release the element lock when posting the message so that any
1672 * (synchronous) message handlers can operate on the element */
1673 result = gst_bus_post (bus, message);
1674 gst_object_unref (bus);
1681 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1682 "not posting message %p: no bus", message);
1683 GST_OBJECT_UNLOCK (element);
1684 gst_message_unref (message);
1690 * _gst_element_error_printf:
1691 * @format: the printf-like format to use, or %NULL
1693 * This function is only used internally by the gst_element_error() macro.
1695 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1701 _gst_element_error_printf (const gchar * format, ...)
1711 va_start (args, format);
1712 buffer = g_strdup_vprintf (format, args);
1718 * gst_element_message_full:
1719 * @element: a #GstElement to send message from
1720 * @type: the #GstMessageType
1721 * @domain: the GStreamer GError domain this message belongs to
1722 * @code: the GError code belonging to the domain
1723 * @text: (allow-none) (transfer full): an allocated text string to be used
1724 * as a replacement for the default message connected to code,
1726 * @debug: (allow-none) (transfer full): an allocated debug message to be
1727 * used as a replacement for the default debugging information,
1729 * @file: the source code file where the error was generated
1730 * @function: the source code function where the error was generated
1731 * @line: the source code line where the error was generated
1733 * Post an error, warning or info message on the bus from inside an element.
1735 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1736 * #GST_MESSAGE_INFO.
1740 void gst_element_message_full
1741 (GstElement * element, GstMessageType type,
1742 GQuark domain, gint code, gchar * text,
1743 gchar * debug, const gchar * file, const gchar * function, gint line)
1745 GError *gerror = NULL;
1749 gboolean has_debug = TRUE;
1750 GstMessage *message = NULL;
1753 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1754 g_return_if_fail (GST_IS_ELEMENT (element));
1755 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1756 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1758 /* check if we send the given text or the default error text */
1759 if ((text == NULL) || (text[0] == 0)) {
1760 /* text could have come from g_strdup_printf (""); */
1762 sent_text = gst_error_get_message (domain, code);
1766 /* construct a sent_debug with extra information from source */
1767 if ((debug == NULL) || (debug[0] == 0)) {
1768 /* debug could have come from g_strdup_printf (""); */
1772 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1774 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1775 file, line, function, name, debug);
1777 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1778 file, line, function, name);
1782 /* create gerror and post message */
1783 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1785 gerror = g_error_new_literal (domain, code, sent_text);
1788 case GST_MESSAGE_ERROR:
1790 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1792 case GST_MESSAGE_WARNING:
1793 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1796 case GST_MESSAGE_INFO:
1797 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1801 g_assert_not_reached ();
1804 gst_element_post_message (element, message);
1806 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1807 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1810 g_error_free (gerror);
1811 g_free (sent_debug);
1816 * gst_element_is_locked_state:
1817 * @element: a #GstElement.
1819 * Checks if the state of an element is locked.
1820 * If the state of an element is locked, state changes of the parent don't
1821 * affect the element.
1822 * This way you can leave currently unused elements inside bins. Just lock their
1823 * state before changing the state from #GST_STATE_NULL.
1827 * Returns: TRUE, if the element's state is locked.
1830 gst_element_is_locked_state (GstElement * element)
1834 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1836 GST_OBJECT_LOCK (element);
1837 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1838 GST_OBJECT_UNLOCK (element);
1844 * gst_element_set_locked_state:
1845 * @element: a #GstElement
1846 * @locked_state: TRUE to lock the element's state
1848 * Locks the state of an element, so state changes of the parent don't affect
1849 * this element anymore.
1853 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1854 * or the elements state-locking needed no change.
1857 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1861 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1863 GST_OBJECT_LOCK (element);
1864 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1866 if (G_UNLIKELY (old == locked_state))
1870 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1871 GST_ELEMENT_NAME (element));
1872 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1874 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1875 GST_ELEMENT_NAME (element));
1876 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1878 GST_OBJECT_UNLOCK (element);
1884 GST_CAT_DEBUG (GST_CAT_STATES,
1885 "elements %s was already in locked state %d",
1886 GST_ELEMENT_NAME (element), old);
1887 GST_OBJECT_UNLOCK (element);
1894 * gst_element_sync_state_with_parent:
1895 * @element: a #GstElement.
1897 * Tries to change the state of the element to the same as its parent.
1898 * If this function returns FALSE, the state of element is undefined.
1900 * Returns: TRUE, if the element's state could be synced to the parent's state.
1905 gst_element_sync_state_with_parent (GstElement * element)
1909 GstStateChangeReturn ret;
1911 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1913 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1914 GstState parent_current, parent_pending;
1916 GST_OBJECT_LOCK (parent);
1917 parent_current = GST_STATE (parent);
1918 parent_pending = GST_STATE_PENDING (parent);
1919 GST_OBJECT_UNLOCK (parent);
1921 /* set to pending if there is one, else we set it to the current state of
1923 if (parent_pending != GST_STATE_VOID_PENDING)
1924 target = parent_pending;
1926 target = parent_current;
1928 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1929 "syncing state (%s) to parent %s %s (%s, %s)",
1930 gst_element_state_get_name (GST_STATE (element)),
1931 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1932 gst_element_state_get_name (parent_current),
1933 gst_element_state_get_name (parent_pending));
1935 ret = gst_element_set_state (element, target);
1936 if (ret == GST_STATE_CHANGE_FAILURE)
1939 gst_object_unref (parent);
1943 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1950 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1951 "syncing state failed (%s)",
1952 gst_element_state_change_return_get_name (ret));
1953 gst_object_unref (parent);
1959 static GstStateChangeReturn
1960 gst_element_get_state_func (GstElement * element,
1961 GstState * state, GstState * pending, GstClockTime timeout)
1963 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1964 GstState old_pending;
1966 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1967 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1969 GST_OBJECT_LOCK (element);
1970 ret = GST_STATE_RETURN (element);
1971 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1972 gst_element_state_change_return_get_name (ret));
1974 /* we got an error, report immediately */
1975 if (ret == GST_STATE_CHANGE_FAILURE)
1978 /* we got no_preroll, report immediately */
1979 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1982 /* no need to wait async if we are not async */
1983 if (ret != GST_STATE_CHANGE_ASYNC)
1986 old_pending = GST_STATE_PENDING (element);
1987 if (old_pending != GST_STATE_VOID_PENDING) {
1988 GTimeVal *timeval, abstimeout;
1991 if (timeout != GST_CLOCK_TIME_NONE) {
1992 glong add = timeout / 1000;
1997 /* make timeout absolute */
1998 g_get_current_time (&abstimeout);
1999 g_time_val_add (&abstimeout, add);
2000 timeval = &abstimeout;
2004 /* get cookie to detect state changes during waiting */
2005 cookie = element->state_cookie;
2007 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2008 "waiting for element to commit state");
2010 /* we have a pending state change, wait for it to complete */
2011 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2012 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2013 /* timeout triggered */
2014 ret = GST_STATE_CHANGE_ASYNC;
2016 if (cookie != element->state_cookie)
2019 /* could be success or failure */
2020 if (old_pending == GST_STATE (element)) {
2021 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2022 ret = GST_STATE_CHANGE_SUCCESS;
2024 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2025 ret = GST_STATE_CHANGE_FAILURE;
2028 /* if nothing is pending anymore we can return SUCCESS */
2029 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2030 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2031 ret = GST_STATE_CHANGE_SUCCESS;
2037 *state = GST_STATE (element);
2039 *pending = GST_STATE_PENDING (element);
2041 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2042 "state current: %s, pending: %s, result: %s",
2043 gst_element_state_get_name (GST_STATE (element)),
2044 gst_element_state_get_name (GST_STATE_PENDING (element)),
2045 gst_element_state_change_return_get_name (ret));
2046 GST_OBJECT_UNLOCK (element);
2053 *state = GST_STATE_VOID_PENDING;
2055 *pending = GST_STATE_VOID_PENDING;
2057 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2059 GST_OBJECT_UNLOCK (element);
2061 return GST_STATE_CHANGE_FAILURE;
2066 * gst_element_get_state:
2067 * @element: a #GstElement to get the state of.
2068 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2070 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2071 * state. Can be %NULL.
2072 * @timeout: a #GstClockTime to specify the timeout for an async
2073 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2075 * Gets the state of the element.
2077 * For elements that performed an ASYNC state change, as reported by
2078 * gst_element_set_state(), this function will block up to the
2079 * specified timeout value for the state change to complete.
2080 * If the element completes the state change or goes into
2081 * an error, this function returns immediately with a return value of
2082 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2084 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2085 * returns the current and pending state immediately.
2087 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2088 * successfully changed its state but is not able to provide data yet.
2089 * This mostly happens for live sources that only produce data in
2090 * %GST_STATE_PLAYING. While the state change return is equivalent to
2091 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2092 * some sink elements might not be able to complete their state change because
2093 * an element is not producing data to complete the preroll. When setting the
2094 * element to playing, the preroll will complete and playback will start.
2096 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2097 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2098 * element is still performing a state change or
2099 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2103 GstStateChangeReturn
2104 gst_element_get_state (GstElement * element,
2105 GstState * state, GstState * pending, GstClockTime timeout)
2107 GstElementClass *oclass;
2108 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2110 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2112 oclass = GST_ELEMENT_GET_CLASS (element);
2114 if (oclass->get_state)
2115 result = (oclass->get_state) (element, state, pending, timeout);
2121 * gst_element_abort_state:
2122 * @element: a #GstElement to abort the state of.
2124 * Abort the state change of the element. This function is used
2125 * by elements that do asynchronous state changes and find out
2126 * something is wrong.
2128 * This function should be called with the STATE_LOCK held.
2133 gst_element_abort_state (GstElement * element)
2137 #ifndef GST_DISABLE_GST_DEBUG
2141 g_return_if_fail (GST_IS_ELEMENT (element));
2143 GST_OBJECT_LOCK (element);
2144 pending = GST_STATE_PENDING (element);
2146 if (pending == GST_STATE_VOID_PENDING ||
2147 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2148 goto nothing_aborted;
2150 #ifndef GST_DISABLE_GST_DEBUG
2151 old_state = GST_STATE (element);
2153 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2154 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2155 gst_element_state_get_name (pending));
2159 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2161 GST_STATE_BROADCAST (element);
2162 GST_OBJECT_UNLOCK (element);
2168 GST_OBJECT_UNLOCK (element);
2173 /* Not static because GstBin has manual state handling too */
2175 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2176 GstState newstate, GstState pending)
2178 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2179 GstMessage *message;
2181 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2182 "notifying about state-changed %s to %s (%s pending)",
2183 gst_element_state_get_name (oldstate),
2184 gst_element_state_get_name (newstate),
2185 gst_element_state_get_name (pending));
2187 if (klass->state_changed)
2188 klass->state_changed (element, oldstate, newstate, pending);
2190 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2191 oldstate, newstate, pending);
2192 gst_element_post_message (element, message);
2196 * gst_element_continue_state:
2197 * @element: a #GstElement to continue the state change of.
2198 * @ret: The previous state return value
2200 * Commit the state change of the element and proceed to the next
2201 * pending state if any. This function is used
2202 * by elements that do asynchronous state changes.
2203 * The core will normally call this method automatically when an
2204 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2206 * If after calling this method the element still has not reached
2207 * the pending state, the next state change is performed.
2209 * This method is used internally and should normally not be called by plugins
2212 * Returns: The result of the commit state change.
2216 GstStateChangeReturn
2217 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2219 GstStateChangeReturn old_ret;
2220 GstState old_state, old_next;
2221 GstState current, next, pending;
2222 GstStateChange transition;
2224 GST_OBJECT_LOCK (element);
2225 old_ret = GST_STATE_RETURN (element);
2226 GST_STATE_RETURN (element) = ret;
2227 pending = GST_STATE_PENDING (element);
2229 /* check if there is something to commit */
2230 if (pending == GST_STATE_VOID_PENDING)
2231 goto nothing_pending;
2233 old_state = GST_STATE (element);
2234 /* this is the state we should go to next */
2235 old_next = GST_STATE_NEXT (element);
2236 /* update current state */
2237 current = GST_STATE (element) = old_next;
2239 /* see if we reached the final state */
2240 if (pending == current)
2243 next = GST_STATE_GET_NEXT (current, pending);
2244 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2246 GST_STATE_NEXT (element) = next;
2248 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2249 GST_OBJECT_UNLOCK (element);
2251 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2252 "committing state from %s to %s, pending %s, next %s",
2253 gst_element_state_get_name (old_state),
2254 gst_element_state_get_name (old_next),
2255 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2257 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2259 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2260 "continue state change %s to %s, final %s",
2261 gst_element_state_get_name (current),
2262 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2264 ret = gst_element_change_state (element, transition);
2270 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2271 GST_OBJECT_UNLOCK (element);
2276 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2277 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2279 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2280 "completed state change to %s", gst_element_state_get_name (pending));
2281 GST_OBJECT_UNLOCK (element);
2283 /* don't post silly messages with the same state. This can happen
2284 * when an element state is changed to what it already was. For bins
2285 * this can be the result of a lost state, which we check with the
2286 * previous return value.
2287 * We do signal the cond though as a _get_state() might be blocking
2289 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2290 _priv_gst_element_state_changed (element, old_state, old_next,
2291 GST_STATE_VOID_PENDING);
2293 GST_STATE_BROADCAST (element);
2300 * gst_element_lost_state:
2301 * @element: a #GstElement the state is lost of
2303 * Brings the element to the lost state. The current state of the
2304 * element is copied to the pending state so that any call to
2305 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2307 * An ASYNC_START message is posted. If the element was PLAYING, it will
2308 * go to PAUSED. The element will be restored to its PLAYING state by
2309 * the parent pipeline when it prerolls again.
2311 * This is mostly used for elements that lost their preroll buffer
2312 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2313 * they will go to their pending state again when a new preroll buffer is
2314 * queued. This function can only be called when the element is currently
2315 * not in error or an async state change.
2317 * This function is used internally and should normally not be called from
2318 * plugins or applications.
2321 gst_element_lost_state (GstElement * element)
2323 GstState old_state, new_state;
2324 GstMessage *message;
2326 g_return_if_fail (GST_IS_ELEMENT (element));
2328 GST_OBJECT_LOCK (element);
2329 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2332 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2333 goto only_async_start;
2335 old_state = GST_STATE (element);
2337 /* when we were PLAYING, the new state is PAUSED. We will also not
2338 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2339 * when we preroll. */
2340 if (old_state > GST_STATE_PAUSED)
2341 new_state = GST_STATE_PAUSED;
2343 new_state = old_state;
2345 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2346 "lost state of %s to %s", gst_element_state_get_name (old_state),
2347 gst_element_state_get_name (new_state));
2349 GST_STATE (element) = new_state;
2350 GST_STATE_NEXT (element) = new_state;
2351 GST_STATE_PENDING (element) = new_state;
2352 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2353 GST_OBJECT_UNLOCK (element);
2355 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2357 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2358 gst_element_post_message (element, message);
2364 GST_OBJECT_UNLOCK (element);
2369 GST_OBJECT_UNLOCK (element);
2371 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2372 gst_element_post_message (element, message);
2378 * gst_element_set_state:
2379 * @element: a #GstElement to change state of.
2380 * @state: the element's new #GstState.
2382 * Sets the state of the element. This function will try to set the
2383 * requested state by going through all the intermediary states and calling
2384 * the class's state change function for each.
2386 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2387 * element will perform the remainder of the state change asynchronously in
2389 * An application can use gst_element_get_state() to wait for the completion
2390 * of the state change or it can wait for a state change message on the bus.
2392 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2393 * #GST_STATE_CHANGE_ASYNC.
2395 * Returns: Result of the state change using #GstStateChangeReturn.
2399 GstStateChangeReturn
2400 gst_element_set_state (GstElement * element, GstState state)
2402 GstElementClass *oclass;
2403 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2405 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2407 oclass = GST_ELEMENT_GET_CLASS (element);
2409 if (oclass->set_state)
2410 result = (oclass->set_state) (element, state);
2416 * default set state function, calculates the next state based
2417 * on current state and calls the change_state function
2419 static GstStateChangeReturn
2420 gst_element_set_state_func (GstElement * element, GstState state)
2422 GstState current, next, old_pending;
2423 GstStateChangeReturn ret;
2424 GstStateChange transition;
2425 GstStateChangeReturn old_ret;
2427 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2429 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2430 gst_element_state_get_name (state));
2432 /* state lock is taken to protect the set_state() and get_state()
2433 * procedures, it does not lock any variables. */
2434 GST_STATE_LOCK (element);
2436 /* now calculate how to get to the new state */
2437 GST_OBJECT_LOCK (element);
2438 old_ret = GST_STATE_RETURN (element);
2439 /* previous state change returned an error, remove all pending
2440 * and next states */
2441 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2442 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2443 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2444 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2447 current = GST_STATE (element);
2448 next = GST_STATE_NEXT (element);
2449 old_pending = GST_STATE_PENDING (element);
2451 /* this is the (new) state we should go to. TARGET is the last state we set on
2453 if (state != GST_STATE_TARGET (element)) {
2454 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2455 "setting target state to %s", gst_element_state_get_name (state));
2456 GST_STATE_TARGET (element) = state;
2457 /* increment state cookie so that we can track each state change. We only do
2458 * this if this is actually a new state change. */
2459 element->state_cookie++;
2461 GST_STATE_PENDING (element) = state;
2463 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2464 "current %s, old_pending %s, next %s, old return %s",
2465 gst_element_state_get_name (current),
2466 gst_element_state_get_name (old_pending),
2467 gst_element_state_get_name (next),
2468 gst_element_state_change_return_get_name (old_ret));
2470 /* if the element was busy doing a state change, we just update the
2471 * target state, it'll get to it async then. */
2472 if (old_pending != GST_STATE_VOID_PENDING) {
2473 /* upwards state change will happen ASYNC */
2474 if (old_pending <= state)
2476 /* element is going to this state already */
2477 else if (next == state)
2479 /* element was performing an ASYNC upward state change and
2480 * we request to go downward again. Start from the next pending
2482 else if (next > state
2483 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2487 next = GST_STATE_GET_NEXT (current, state);
2488 /* now we store the next state */
2489 GST_STATE_NEXT (element) = next;
2490 /* mark busy, we need to check that there is actually a state change
2491 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2492 * the default element change_state function has no way to know what the
2493 * old value was... could consider this a FIXME...*/
2494 if (current != next)
2495 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2497 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2499 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2500 "%s: setting state from %s to %s",
2501 (next != state ? "intermediate" : "final"),
2502 gst_element_state_get_name (current), gst_element_state_get_name (next));
2504 /* now signal any waiters, they will error since the cookie was incremented */
2505 GST_STATE_BROADCAST (element);
2507 GST_OBJECT_UNLOCK (element);
2509 ret = gst_element_change_state (element, transition);
2511 GST_STATE_UNLOCK (element);
2513 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2514 gst_element_state_change_return_get_name (ret));
2520 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2521 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2522 "element was busy with async state change");
2523 GST_OBJECT_UNLOCK (element);
2525 GST_STATE_UNLOCK (element);
2527 return GST_STATE_CHANGE_ASYNC;
2532 * gst_element_change_state:
2533 * @element: a #GstElement
2534 * @transition: the requested transition
2536 * Perform @transition on @element.
2538 * This function must be called with STATE_LOCK held and is mainly used
2541 * Returns: the #GstStateChangeReturn of the state transition.
2543 GstStateChangeReturn
2544 gst_element_change_state (GstElement * element, GstStateChange transition)
2546 GstElementClass *oclass;
2547 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2549 oclass = GST_ELEMENT_GET_CLASS (element);
2551 /* call the state change function so it can set the state */
2552 if (oclass->change_state)
2553 ret = (oclass->change_state) (element, transition);
2555 ret = GST_STATE_CHANGE_FAILURE;
2558 case GST_STATE_CHANGE_FAILURE:
2559 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2560 "have FAILURE change_state return");
2561 /* state change failure */
2562 gst_element_abort_state (element);
2564 case GST_STATE_CHANGE_ASYNC:
2568 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2569 "element will change state ASYNC");
2571 target = GST_STATE_TARGET (element);
2573 if (target > GST_STATE_READY)
2576 /* else we just continue the state change downwards */
2577 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2578 "forcing commit state %s <= %s",
2579 gst_element_state_get_name (target),
2580 gst_element_state_get_name (GST_STATE_READY));
2582 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2585 case GST_STATE_CHANGE_SUCCESS:
2586 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2587 "element changed state SUCCESS");
2588 /* we can commit the state now which will proceeed to
2590 ret = gst_element_continue_state (element, ret);
2592 case GST_STATE_CHANGE_NO_PREROLL:
2593 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2594 "element changed state NO_PREROLL");
2595 /* we can commit the state now which will proceeed to
2597 ret = gst_element_continue_state (element, ret);
2600 goto invalid_return;
2603 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2608 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2616 GST_OBJECT_LOCK (element);
2617 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2618 g_critical ("%s: unknown return value %d from a state change function",
2619 GST_ELEMENT_NAME (element), ret);
2621 /* we are in error now */
2622 ret = GST_STATE_CHANGE_FAILURE;
2623 GST_STATE_RETURN (element) = ret;
2624 GST_OBJECT_UNLOCK (element);
2630 /* gst_iterator_fold functions for pads_activate
2631 * Stop the iterator if activating one pad failed. */
2633 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2635 GstPad *pad = g_value_get_object (vpad);
2636 gboolean cont = TRUE;
2638 if (!(cont = gst_pad_set_active (pad, *active)))
2639 g_value_set_boolean (ret, FALSE);
2644 /* returns false on error or early cutout of the fold, true if all
2645 * pads in @iter were (de)activated successfully. */
2647 iterator_activate_fold_with_resync (GstIterator * iter,
2648 GstIteratorFoldFunction func, gpointer user_data)
2650 GstIteratorResult ires;
2653 /* no need to unset this later, it's just a boolean */
2654 g_value_init (&ret, G_TYPE_BOOLEAN);
2655 g_value_set_boolean (&ret, TRUE);
2658 ires = gst_iterator_fold (iter, func, &ret, user_data);
2660 case GST_ITERATOR_RESYNC:
2661 /* need to reset the result again */
2662 g_value_set_boolean (&ret, TRUE);
2663 gst_iterator_resync (iter);
2665 case GST_ITERATOR_DONE:
2666 /* all pads iterated, return collected value */
2669 /* iterator returned _ERROR or premature end with _OK,
2670 * mark an error and exit */
2671 g_value_set_boolean (&ret, FALSE);
2676 /* return collected value */
2677 return g_value_get_boolean (&ret);
2680 /* is called with STATE_LOCK
2682 * Pads are activated from source pads to sinkpads.
2685 gst_element_pads_activate (GstElement * element, gboolean active)
2690 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2691 "pads_activate with active %d", active);
2693 iter = gst_element_iterate_src_pads (element);
2695 iterator_activate_fold_with_resync (iter,
2696 (GstIteratorFoldFunction) activate_pads, &active);
2697 gst_iterator_free (iter);
2698 if (G_UNLIKELY (!res))
2701 iter = gst_element_iterate_sink_pads (element);
2703 iterator_activate_fold_with_resync (iter,
2704 (GstIteratorFoldFunction) activate_pads, &active);
2705 gst_iterator_free (iter);
2706 if (G_UNLIKELY (!res))
2709 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2710 "pads_activate successful");
2717 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2718 "source pads_activate failed");
2723 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2724 "sink pads_activate failed");
2729 /* is called with STATE_LOCK */
2730 static GstStateChangeReturn
2731 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2733 GstState state, next;
2734 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2736 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2738 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2739 next = GST_STATE_TRANSITION_NEXT (transition);
2741 /* if the element already is in the given state, we just return success */
2742 if (next == GST_STATE_VOID_PENDING || state == next)
2745 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2746 "default handler tries setting state from %s to %s (%04x)",
2747 gst_element_state_get_name (state),
2748 gst_element_state_get_name (next), transition);
2750 switch (transition) {
2751 case GST_STATE_CHANGE_NULL_TO_READY:
2753 case GST_STATE_CHANGE_READY_TO_PAUSED:
2754 if (!gst_element_pads_activate (element, TRUE)) {
2755 result = GST_STATE_CHANGE_FAILURE;
2758 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2760 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2762 case GST_STATE_CHANGE_PAUSED_TO_READY:
2763 case GST_STATE_CHANGE_READY_TO_NULL:
2764 /* deactivate pads in both cases, since they are activated on
2765 ready->paused but the element might not have made it to paused */
2766 if (!gst_element_pads_activate (element, FALSE)) {
2767 result = GST_STATE_CHANGE_FAILURE;
2771 /* this will catch real but unhandled state changes;
2772 * can only be caused by:
2773 * - a new state was added
2774 * - somehow the element was asked to jump across an intermediate state
2776 g_warning ("Unhandled state change from %s to %s",
2777 gst_element_state_get_name (state),
2778 gst_element_state_get_name (next));
2785 GST_OBJECT_LOCK (element);
2786 result = GST_STATE_RETURN (element);
2787 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2788 "element is already in the %s state",
2789 gst_element_state_get_name (state));
2790 GST_OBJECT_UNLOCK (element);
2797 * gst_element_get_factory:
2798 * @element: a #GstElement to request the element factory of.
2800 * Retrieves the factory that was used to create this element.
2802 * Returns: (transfer none): the #GstElementFactory used for creating this
2803 * element. no refcounting is needed.
2806 gst_element_get_factory (GstElement * element)
2808 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2810 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2814 gst_element_dispose (GObject * object)
2816 GstElement *element = GST_ELEMENT_CAST (object);
2820 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2822 if (GST_STATE (element) != GST_STATE_NULL)
2825 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2826 "removing %d pads", g_list_length (element->pads));
2827 /* first we break all our links with the outside */
2828 while (element->pads && element->pads->data) {
2829 /* don't call _remove_pad with NULL */
2830 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2832 if (G_UNLIKELY (element->pads != NULL)) {
2833 g_critical ("could not remove pads from element %s",
2834 GST_STR_NULL (GST_OBJECT_NAME (object)));
2837 GST_OBJECT_LOCK (element);
2838 clock_p = &element->clock;
2839 bus_p = &element->bus;
2840 gst_object_replace ((GstObject **) clock_p, NULL);
2841 gst_object_replace ((GstObject **) bus_p, NULL);
2842 GST_OBJECT_UNLOCK (element);
2844 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2846 G_OBJECT_CLASS (parent_class)->dispose (object);
2855 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2857 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2859 "You need to explicitly set elements to the NULL state before\n"
2860 "dropping the final reference, to allow them to clean up.\n"
2861 "This problem may also be caused by a refcounting bug in the\n"
2862 "application or some element.\n",
2863 GST_OBJECT_NAME (element),
2864 gst_element_state_get_name (GST_STATE (element)),
2865 is_locked ? " (locked)" : "");
2871 gst_element_finalize (GObject * object)
2873 GstElement *element = GST_ELEMENT_CAST (object);
2875 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2877 g_cond_free (element->state_cond);
2878 g_static_rec_mutex_free (&element->state_lock);
2880 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2882 G_OBJECT_CLASS (parent_class)->finalize (object);
2886 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2890 g_return_if_fail (GST_IS_ELEMENT (element));
2892 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2894 GST_OBJECT_LOCK (element);
2895 bus_p = &GST_ELEMENT_BUS (element);
2896 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2897 GST_OBJECT_UNLOCK (element);
2901 * gst_element_set_bus:
2902 * @element: a #GstElement to set the bus of.
2903 * @bus: (transfer none): the #GstBus to set.
2905 * Sets the bus of the element. Increases the refcount on the bus.
2906 * For internal use only, unless you're testing elements.
2911 gst_element_set_bus (GstElement * element, GstBus * bus)
2913 GstElementClass *oclass;
2915 g_return_if_fail (GST_IS_ELEMENT (element));
2917 oclass = GST_ELEMENT_GET_CLASS (element);
2919 if (oclass->set_bus)
2920 oclass->set_bus (element, bus);
2924 * gst_element_get_bus:
2925 * @element: a #GstElement to get the bus of.
2927 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2928 * bus for the application.
2930 * Returns: (transfer full): the element's #GstBus. unref after usage.
2935 gst_element_get_bus (GstElement * element)
2937 GstBus *result = NULL;
2939 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2941 GST_OBJECT_LOCK (element);
2942 if ((result = GST_ELEMENT_BUS (element)))
2943 gst_object_ref (result);
2944 GST_OBJECT_UNLOCK (element);
2946 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,